Inspiron 531: SATA2 and SATA3 not working

Hi there! Today i got my new Inspiron 531 Desktop. The primary hard disk is connected to SATA 0 and the DVD Writer to SATA 1. I want to install a second hard disk on the SATA 2 port, but it is not recognized by the BIOS. I also can not find an option in the BIOS to enable the 2 non-working SATA ports. I have verified that the problem lies in the SATA ports, because when I connect the 2nd hard disk to SATA 1 and the DVD Writer to SATA 2, the hard disk works and the DVD Writer doesn't. Is there an option to enable the 2 additional SATA ports? Thank you for your help, TheTribe.

Tribe, so how did you do it? I have an Inspiron 530 and just installed a 2nd hard drive. SATA 0 and SATA 1 were used by the hard drive and CD ROM. I hooked up the 2nd hard drive to SATA 3 and also a power cable.

When going to the BIOS and to the Drive section, all the SATA lines are not highlighted so I can't get to them. It does show SATA 0 & 1 being used but SATA 2 & 3 open.

I first looked there too and didn't find the option. As I am currently writing from my computer I can not tell you exactly where you can find the option but it's in another menu item. There is something like SATA options, where you can enable the second SATA controller.